Here's what I've been able to put together based on several Metro sources, two of which were there.

Boiled down, sources say the tragedy was a perfect storm, combining a careless employee and failure by management at the yard to consistently enforce fundamental safety rules.

The employee was struck inside a car washing facility. The area outside the car wash served as an unofficial smoking area for car mechanics because there wasn't an officially designated smoking area for them, sources say.

For the mechanics to leave the smoking area and return to work often required crossing live track. The route through the car wash, which involves entering live tracks, was a commonly used shortcut, sources said.

According to Metro rules, any employee entering live track must request permission. This rule appears to have been loosely enforced at Shady Grove, if at all.

The employee did not request permission to enter a live track area from the yard master, say two sources. But this was a common practice, they said, and management turned a blind eye.

"It was not a good area to have people smoking," said a source. "The way they crossed the tracks like that, it was only a matter of time. No one ever said anything. If you bring stuff up like this at Metro, you risk becoming a black sheep. There's too much go along to get along."

Further complicating the situation was that trains were entering the car wash from the opposite direction from which they normally do. Sources conflict as to how long that had been going on, but all said it was widely known that trains were flowing differently from the norm because of work in the area.

"This guy should have known," said a source.

Adding to chain of events that led to the injury is that the area around the door the mechanic used is a widely known structural blind spot.

Another potential issue is that signs on the door the employee used to enter the car wash, which warned of moving trains inside, had been removed and had not yet been replaced, said a car mechanic at the yard.

"I don't think that's a big deal," said one source.

Once the impact occurred, the employee was dragged 38 feet, according to Metro's own diagram (above).

One source familiar with the case said "we all cannot understand how a train going at less than five miles per hour would have this effect. Even if he stepped into the path of the train, at that speed, he should have been able to either get knocked back or into the pit between the rails. Most of us suspect the train was traveling at a greater speed than five miles per hour."

To add to the horror of the incident, at some point, while the employee was pinned under the train for over an hour as rescue workers tried to free him, "750 volts was energized on the rail he was pinned against," confirmed two sources.

Those there said he "let out a loud deathly scream when the voltage came back up," said a source.

They didn't know if third-rail power was inadvertently restored or was gapped (gapping is when third rail power is dropped in one place, but the train picks it up from another section that hasn't been dropped and bridges the "gap" to re-energize it.) from the rear of the train.

The injured employee remains in critical condition.

After the incident, Metro issued a "safety stand down." I asked a source what that means.

"Considering all the stand downs we've had--nothing," they said.

Sources added that since each new Metro regime comes in with new rules, the rules all pile on top of one another, often conflicting and "after a while you tune them out."